1. Field of the Invention
This invention concerns a lightweight, reusable, convenient insect monitoring and trapping device for capturing flying adult insects, particularly whiteflies. In the preferred embodiment, the trap is a three element snap together unit which is not sticky and does not require bait. The trap is designed to exploit behavioral and flight characteristics to trap the insects.
2. Background of the Invention
Various traps and devices are available for capturing flying insects. However, most traps require the use of adhesives or bait or attractants, which are messy and must be replaced often. Many of the traps are complicated and difficult to manufacture inexpensively. For example, U.S. Pat. Nos. 5,392,560 and 5,461,822 describe traps for flying insects which require bait or a pheromone attractant to lure the insects to the trap. U.S. Pat. No. 5,090,153 requires both bait and an adhesive area to trap the insects. Yellow sticky card traps are commonly used for monitoring adult whitefly activity in the field and for control of whitefly populations in greenhouses. Disadvantages of sticky card traps include the tendency of the trap's adhesive to become clogged with non-target insects and dust, sticky card traps are not reusable, the adhesive is messy and difficult to handle, a microscope must be used as an aid to count the trapped small insects such as whiteflies, and specimens are distorted and cannot be used for further taxonomic study, or molecular genetic analysis.
Whiteflies are distributed worldwide in tropical and subtropical areas as well as temperate zones (Byrne et al. 1990). There are 37 species identified in the Bemisia genus (Mound & Halsey 1978). Bemisia tabaci (Gennadius) is one of the most serious economic pests attacking over 300 species of plants. The newly described species Bemisia argentifolii Bellows & Perring (Bellows et al. 1994) probably first found in Florida (Harmon & Salguero 1987) has an even wider host range and is more prolific than B. tabaci (Gill 1992). The economic losses caused by the new species in the three year period from May 1991 to April 1994 in the Imperial Valley, California alone was close to 1 billion dollars (Birdsall et al. 1995). Beltwide cotton losses due to B. argentifolii colonization was estimated at about 16,000 bales in 1994 (Williams 1995). Further, lint quality was reduced because of stickiness and associated sooty-mold (Cladosporium spp.) development. This new strain or a new species has an expanded host range and attacks numerous commercially grown crops as well as ornamentals and many weed hosts (Perring et al. 1993, Bellows et al. 1994). This has made it particularly difficult to control. For example, in the desert cultivated crop-growing areas of Arizona and California, sequential planting of cole crops, curcurbits, cotton, and alfalfa offers a continuum of year-round susceptible host material and the opportunity for whiteflies to move within and among cropping systems to expand population development. Control methods for the new species are urgently needed.
Basu (1995) indicated that color may be the only factor in B. tabaci host location. Berlinger (1986) found B. tabaci attracted to a yellow incandescent bulb. Mound (1962) reported B. tabaci was attracted to two wavelengths of transmitted light, the blue/ultra-violet and the yellow area of the spectrum. Other whitefly species such as Trialeurodes abutilonea are also attracted to yellow (Lloyd 1921). Vernon and Gillespie (1990) noted that a yellow pigment with high reflective intensity around 550 nm effectively attracted T. vaporariorum. These results have led to the use of yellow sticky card traps (Olson Products, Inc., Medina, OH) for monitoring whitefly population densities (e.g. Heinz et al. 1992, Natwick et al. 1995) and yellow plastic mulches for crop protection from whiteflies (Berlinger et al. 1983). In laboratory studies of B. argentifolii feeding behavior, we found that adults initially flew from host leaves toward light, but after landing on new host leaves, they walked to shaded areas, usually the undersides of leaves (Chu et al. 1995). Based on this behavior and yellow color orientation, we developed a whitefly trap that can be used for monitoring adult density under field conditions and for adult control in greenhouses. We refer to our whitefly trap as the CC trap.